Learn More
When our two eyes view incongruent images, we experience binocular rivalry: An ongoing cycle of dominance periods of either image and transition periods when both are visible. Two key forces underlying this process are adaptation of and inhibition between the images' neural representations. Models based on these factors meet the constraints posed by data on(More)
Existing neural explanations of spontaneous percept switching under steady viewing of an ambiguous stimulus do not fit the fact that stimulus interruptions cause the same percept to reappear across many ON/OFF cycles. We present a simple neural model that explains the observed behavior and predicts several more complicated percept sequences, without(More)
At the onset of bistable stimuli, the brain needs to choose which of the competing perceptual interpretations will first reach awareness. Stimulus manipulations and cognitive control both influence this choice process, but the underlying mechanisms and interactions remain poorly understood. Using intermittent presentation of bistable visual stimuli, we(More)
When visual input is inconclusive, does previous experience aid the visual system in attaining an accurate perceptual interpretation? Prolonged viewing of a visually ambiguous stimulus causes perception to alternate between conflicting interpretations. When viewed intermittently, however, ambiguous stimuli tend to evoke the same percept on many consecutive(More)
EEG signals have been considered to result either from random processes or to be generated by non-linear dynamic systems exhibiting chaotic behaviour. In the latter case, the system may behave as a deterministic chaotic attractor. The complexity of the attractor can be characterized by the correlation dimension that can be computed from one signal generated(More)
Protection against infection hinges on a close interplay between the innate immune system and the adaptive immune system. Depending on the type and context of a pathogen, the innate system instructs the adaptive immune system to induce an appropriate immune response. Here, we hypothesize that the adaptive immune system stores these instructions by changing(More)
Perceptual dissociation of moving plaid patterns into independently moving bar gratings occurs most readily when the grating signals are combined as if the bars were semi-transparent objects (Ramachandran, V. S. (1990) in: AI and the Eye. Wiley, Chichester, pp. 21-77. Stoner, G. R., Albright, T. D. and Ramachandran, V. S. (1990) Nature 344, 153-155). These(More)
Measurements on the average telomere lengths of normal human naive and memory T cells suggested that 1) naive and memory human T cells have similar division rates, and 2) that the difference between naive and memory cells reflects the degree of clonal expansion during normal immune reactions. Here we develop mathematic models describing how the population(More)
Humans do not confound the motion of shadows cast upon a surface with the motion of the surface itself, although schemes that propose recombination of orientation-selective motion signals into a rigid motion percept of two-dimensional patterns would predict that they should do so. We propose a simple scheme that avoids recombination and instead attributes(More)